This invention relates to the sulfhydrolysis of di-linear (C.sub.4 -C.sub.18) alkyl sulfides at elevated temperature in the presence of a specified transition alumina catalyst to produce high purity linear (C.sub.4 -C.sub.18) alkyl mercaptan. More particularly, it relates to the reaction of a di-linear (C.sub.4 -C.sub.18) alkyl sulfide (RSR) with hydrogen sulfide (H.sub.2 S) at a temperature preferably ranging from about 150.degree. up to about 400.degree. C. in the presence of a specified transition alumina, to produce, the corresponding alkyl mercaptan in high purity and good yield.